In a mobile communication system, a call-processing node that performs call processing is subject to planned stops for the purpose of maintenance or the like, and sudden stops due to occurrence of malfunctions. In a call processing system of the mobile communication system, redundancy is required such that a communication call is not disconnected in either of the cases described above. Therefore, a call-processing node of an active system (act) and a call-processing node of a standby system (sby) are provided to perform redundancy (multiplexing) of a device (e.g., see Patent Literature 1).